我在ViewControllerA(Parent)上有一个按钮,我想更新ViewControllerB(Child)中的一个变量。 ViewControllerB是ViewControllerA中的容器视图。如何将数据从父视图控制器多次传递给Swift中的Container VC子项?
这是我想从父ViewControllerA按下按钮更新多次在ViewControllerB变量:
@IBOutlet weak var childViewHeight: NSLayoutConstraint!
因为孩子看,ViewControllerB,通过嵌入SEGUE连接,看来我只能传递通过prepareForSegue
方法将数据从ViewControllerA传送到ViewControllerB。 performSegue
方法导致程序崩溃,出现SIGABRT
错误。
我知道从一个单独的类或视图控制器中尝试更新IBOutlet
通常被认为是不好的做法,但我需要一种方法来按下ViewControllerA上的按钮同时更改ViewControllerA和ViewControllerB的高度约束。
如果在我目前的方法中这是不可能的,请给我另一个建议,告诉我如何重新设计我的应用程序以使其成为可能。
更新 - 这是导致崩溃的代码:
@IBAction func button(_ sender: AnyObject) {
performSegue(withIdentifier: "seg", sender: self)
}
更新 - 这是当我输入在调试控制台“BT”的结果:
* thread #1: tid = 0x1fcdd, 0x000000010d9b1f06 libsystem_kernel.dylib`__pthread_kill + 10, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
frame #0: 0x000000010d9b1f06 libsystem_kernel.dylib`__pthread_kill + 10
frame #1: 0x000000010dad24ec libsystem_pthread.dylib`pthread_kill + 90
frame #2: 0x000000010d7040b3 libsystem_c.dylib`abort + 129
frame #3: 0x000000010d9d043a libc++abi.dylib`abort_message + 266
frame #4: 0x000000010d9f4a9f libc++abi.dylib`default_terminate_handler() + 267
frame #5: 0x000000010c7b559f libobjc.A.dylib`_objc_terminate() + 103
frame #6: 0x000000010d9f1c09 libc++abi.dylib`std::__terminate(void (*)()) + 8
frame #7: 0x000000010d9f1894 libc++abi.dylib`__cxa_rethrow + 99
frame #8: 0x000000010c7b54b7 libobjc.A.dylib`objc_exception_rethrow + 40
frame #9: 0x000000010a2eebf1 CoreFoundation`CFRunLoopRunSpecific + 433
frame #10: 0x000000010f6d7a48 GraphicsServices`GSEventRunModal + 161
frame #11: 0x000000010ad27e8b UIKit`UIApplicationMain + 159
* frame #12: 0x000000010a1c60cf ContainerVC2`main + 111 at AppDelegate.swift:12
frame #13: 0x000000010d6586bd libdyld.dylib`start + 1
更新 - 在这里是“bt”控制台输出,并带有异常断点:
* thread #1: tid = 0x219bd, 0x000000010afca2ee libobjc.A.dylib`objc_exception_throw, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x000000010afca2ee libobjc.A.dylib`objc_exception_throw
frame #1: 0x0000000108b7dec2 CoreFoundation`+[NSException raise:format:arguments:] + 98
frame #2: 0x0000000109079455 Foundation`-[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
frame #3: 0x0000000109f65309 UIKit`__67-[UIStoryboardEmbedSegueTemplate newDefaultPerformHandlerForSegue:]_block_invoke + 438
frame #4: 0x0000000109ce05e4 UIKit`-[UIStoryboardSegueTemplate _performWithDestinationViewController:sender:] + 453
frame #5: 0x0000000109ce03ee UIKit`-[UIStoryboardSegueTemplate _perform:] + 82
frame #6: 0x00000001096dc45b UIKit`-[UIViewController performSegueWithIdentifier:sender:] + 99
* frame #7: 0x00000001089d99b3 ContainerVC2`ViewController1.button(sender=0x00007fff57224658, self=0x00007fcddb707cb0) ->() + 131 at ViewController.swift:9
frame #8: 0x00000001089d9a26 ContainerVC2`@objc ViewController1.button(AnyObject) ->() + 54 at ViewController.swift:0
frame #9: 0x000000010953eb6f UIKit`-[UIApplication sendAction:to:from:forEvent:] + 83
frame #10: 0x00000001096bf927 UIKit`-[UIControl sendAction:to:forEvent:] + 67
frame #11: 0x00000001096bfc08 UIKit`-[UIControl _sendActionsForEvents:withEvent:] + 388
frame #12: 0x00000001096be6aa UIKit`-[UIControl touchesBegan:withEvent:] + 414
frame #13: 0x00000001095aabbd UIKit`-[UIWindow _sendTouchesForEvent:] + 1188
frame #14: 0x00000001095ac8d6 UIKit`-[UIWindow sendEvent:] + 3984
frame #15: 0x000000010955a1e1 UIKit`-[UIApplication sendEvent:] + 281
frame #16: 0x0000000109d1502f UIKit`__dispatchPreprocessedEventFromEventQueue + 3314
frame #17: 0x0000000109d0dc4e UIKit`__handleEventQueue + 4879
frame #18: 0x0000000108b1fcb1 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
frame #19: 0x0000000108b04c6c CoreFoundation`__CFRunLoopDoSources0 + 556
frame #20: 0x0000000108b04156 CoreFoundation`__CFRunLoopRun + 918
frame #21: 0x0000000108b03b5d CoreFoundation`CFRunLoopRunSpecific + 285
frame #22: 0x000000010deeca48 GraphicsServices`GSEventRunModal + 161
frame #23: 0x000000010953ce8b UIKit`UIApplicationMain + 159
frame #24: 0x00000001089db0cf ContainerVC2`main + 111 at AppDelegate.swift:12
frame #25: 0x000000010be6d6bd libdyld.dylib`start + 1
这里是我之后的“bt”输出点击“继续执行程序”按钮一次:
* thread #1: tid = 0x219bd, 0x000000010c206607 libc++abi.dylib`__cxa_throw, queue = 'com.apple.main-thread', stop reason = breakpoint 1.2
frame #0: 0x000000010c206607 libc++abi.dylib`__cxa_throw
frame #1: 0x000000010afca443 libobjc.A.dylib`objc_exception_throw + 341
frame #2: 0x0000000108b7dec2 CoreFoundation`+[NSException raise:format:arguments:] + 98
frame #3: 0x0000000109079455 Foundation`-[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
frame #4: 0x0000000109f65309 UIKit`__67-[UIStoryboardEmbedSegueTemplate newDefaultPerformHandlerForSegue:]_block_invoke + 438
frame #5: 0x0000000109ce05e4 UIKit`-[UIStoryboardSegueTemplate _performWithDestinationViewController:sender:] + 453
frame #6: 0x0000000109ce03ee UIKit`-[UIStoryboardSegueTemplate _perform:] + 82
frame #7: 0x00000001096dc45b UIKit`-[UIViewController performSegueWithIdentifier:sender:] + 99
* frame #8: 0x00000001089d99b3 ContainerVC2`ViewController1.button(sender=0x00007fff57224658, self=0x00007fcddb707cb0) ->() + 131 at ViewController.swift:9
frame #9: 0x00000001089d9a26 ContainerVC2`@objc ViewController1.button(AnyObject) ->() + 54 at ViewController.swift:0
frame #10: 0x000000010953eb6f UIKit`-[UIApplication sendAction:to:from:forEvent:] + 83
frame #11: 0x00000001096bf927 UIKit`-[UIControl sendAction:to:forEvent:] + 67
frame #12: 0x00000001096bfc08 UIKit`-[UIControl _sendActionsForEvents:withEvent:] + 388
frame #13: 0x00000001096be6aa UIKit`-[UIControl touchesBegan:withEvent:] + 414
frame #14: 0x00000001095aabbd UIKit`-[UIWindow _sendTouchesForEvent:] + 1188
frame #15: 0x00000001095ac8d6 UIKit`-[UIWindow sendEvent:] + 3984
frame #16: 0x000000010955a1e1 UIKit`-[UIApplication sendEvent:] + 281
frame #17: 0x0000000109d1502f UIKit`__dispatchPreprocessedEventFromEventQueue + 3314
frame #18: 0x0000000109d0dc4e UIKit`__handleEventQueue + 4879
frame #19: 0x0000000108b1fcb1 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
frame #20: 0x0000000108b04c6c CoreFoundation`__CFRunLoopDoSources0 + 556
frame #21: 0x0000000108b04156 CoreFoundation`__CFRunLoopRun + 918
frame #22: 0x0000000108b03b5d CoreFoundation`CFRunLoopRunSpecific + 285
frame #23: 0x000000010deeca48 GraphicsServices`GSEventRunModal + 161
frame #24: 0x000000010953ce8b UIKit`UIApplicationMain + 159
frame #25: 0x00000001089db0cf ContainerVC2`main + 111 at AppDelegate.swift:12
frame #26: 0x000000010be6d6bd libdyld.dylib`start + 1
更新 - prepareforsegue
代码:
override func prepare(for segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "seg" {
var vcB: ViewControllerB?
vcB = segue.desinationViewController as? ViewControllerB
}
1)当你说“视图”时,你真的是指“视图控制器”吗? 2)如果A在'prepareForSegue'方法中引用B,它可以保存该引用以便稍后使用。 3)你可以添加崩溃到你的问题的代码? 4)您需要在segue期间更新B中的不同属性,然后在加载B的视图时设置出口。 –
@PhillipMills 1)是的(现在更新澄清)2)你能解释它如何保存一个参考以备后用? 3)它是perfromSegue方法(上面添加的代码)4)有没有办法做到这一点,当在ViewControllerA中按下按钮时,会立即更新childViewHeight变量?你能举一个例子说明这个(或者2)在代码中的样子吗? – PlateReverb
假设你使用Swift 3并且正确定义了segue,那么为什么该行会崩溃没有明显的原因。我建议去Xcode的断点导航器,并设置所有例外的断点。当您的应用程序停止时,在调试控制台中输入“bt”并将结果添加到您的问题中。 –